Bioinformation detection device utilizing air pressure variation

ABSTRACT

A bioinformation detection device, comprising a three-layer structure having a base, an elastic body, and a cover body, wherein a closed space is formed by a load applied to the structure, a strain detection element is sealed in the closed space, and an air pressure variation caused by bioinformation is converted into an electric signal and taken out, whereby the detail bioinformation can be accurately provided for a long time.

TECHNICAL FIELD

This invention relates to a device for detection of bioinformation, andparticularly to such a device relying on changes in pneumatic pressureunder the biological load for bioinformation detection. Moreparticularly, the invention pertains to a device including a hollow,open-top pedestal, complete with a load-sensing cap, in which there ismounted a strain sensor for sensing changes in pneumatic pressure due tothe biological load exerted via a leg of a bed, chair, or the like onthe load-sensing cap. The term “strain sensor” should be construed tomean any device capable of sensing strain, as by generating a voltage orvarying in electrical resistance, examples being a piezoelectricelement, strain gage, and semiconductor sensor.

The usual conventional practice for measurement of biological parameterssuch as pulsation, breathings, and bodily movements has been to affixelectrodes or probes to the humans or animals. The signals picked up bythese devices are sent over cables or cords to the associatedinstruments for measurement or observation.

This conventional practice is objectionable in that the electrodes orprobes are easy to be displaced on or detached from the human or animalbodies while in use, failing to pick up the signals from where theyshould. Another objection is that the connecting wires such as cords aresusceptible to breakage under certain circumstances of usage, as attheir intersections or folds under the bedding. The breaking of theconnecting wires may lead to the danger of electrification as when theinstrument is powered from a commercial power supply. What is more, theconnecting wires lend themselves to undesired functioning as antennas,attracting external electromagnetic noise.

There has been a known method of bioinformation measurement other thanthe attachment of electrodes or probes to the human or animal bodies. Itemploys an air-filled bag or mat laid, for example, under part or wholeof the recumbent human body. Pressure variations created inside the bagor mat are detected with pressure sensors.

Although free from the shortcomings of the first recited prior art, thisalternative method possesses the drawback that the air bag or mat mustbe much larger than the human body, or two or more bags or mats put tojoint use, in order to allow for some body movements thereon. It is alsoa serious demerit of this alternative method that the air bags or matsare themselves so elastic that they absorb pressure variations thereon.These devices are therefore unfit for applications where very finesignals must be handled.

DISCLOSURE OF INVENTION

The present invention seeks to accurately detect all the requiredbioinformation from both humans and animals as they lie on a bed, chairor the like, without need for attachment of probes or the like to thebodies or for provision of outsize air bags or mats.

For the attainment of these objects, the present invention proposes abioinformation detector having a pedestal and a cap thereon which incombination define an enclosed space accommodating a strain sensor. Thedetector is designed to be placed under a leg of a bed, chair or thelike, where the weight of the biological body concentrates. The desiredbioinformation is collected by detecting changes in the pressure of theenclosed space by the strain sensor.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded perspective view of the bioinformation detectorembodying the novel concepts of this invention;

FIG. 2 is an axial section through the bioinformation detector of FIG. 1assembled and fitted with electric means;

FIG. 3 is a view similar to FIG. 3 but showing another preferred form ofbioinformation detector according to the invention; and

FIG. 4 is a vertical section through still another preferred form ofbioinformation detector incorporating a plurality of detector units eachconstructed ass in FIGS. 1 and 2.

BEST MODE FOR CARRYING OUT THE INVENTION

The mechanical organization of the bioinformation detector according tothe invention will be apparent from a study of FIG. 1, from whichelectrical parts have been omitted for simplicity. The reference numeral1 in this figure generally denotes a pedestal in the shape of anup-standing, hollow, open-top cylinder, complete with three annularsteps 11, 12 and 13 to provide three coaxial cylindrical parts whichdiminish in diameter from the bottom upwards.

The pedestal 1 defines a cavity 14 extending coaxially from the top ofthe pedestal and terminating short of its bottom. Although shown to becylindrical in shape, the cavity 14 could be of various other shapes aslong as they do not run counter to the constructional and operationalfeatures of the bioinformation detector hereinafter set forth.

The pedestal 1 is furnished with means 15 for adjustment of static airpressure in the cavity 14. The pressure adjustment means 15 include anair passageway extending radially of the pedestal 1 to communicate thecavity 14 with atmosphere. The air passageway is equipped with valvemeans for placing the cavity 14 in and out of communication withatmosphere as well as for permitting controlled airflow through thepassageway for optimum static pressure.

At 2 in FIG. 1 is seen a sealing ring of elastic material with acircular cross-sectional shape. The sealing ring 2 has an insidediameter approximately equal to the inside diameter of the pedestal step12, and an outside diameter approximately equal to its outside diameter.The sealing ring 2 can therefore fit over the step 13 so as to rest onthe step 12.

Shown also in FIG. 1 is a cap 3 having a cavity 31 extending upwardlyfrom its bottom and terminating short of its top. The cap cavity 31 hasa diameter somewhat greater than the outside diameter of the pedestalstep 12. The cap 3 is also provided with an air passageway andassociated valve means 32 for placing the cap cavity 31 in and out ofcommunication with atmosphere, with a capability of permitting airflowthrough the passageway at a controlled rate for optimization of staticair pressure in the cap cavity.

FIG. 2 depicts the pedestal 1, sealing ring 2, and cap 3 of FIG. 1assembled together with some additional means to provide thebioinformation detector according to the invention. The pedestal 1 hasits open top closed by a diaphragm 4 which has its peripheral marginaledge affixed to the step 13. A strain sensor 5 is attached to theunderside of the diaphragm 14 and electrically connected to a circuitboard 6 on the bottom of the pedestal cavity 14. The circuit board 6 isfurnished with means for amplifying the signal generated by the strainsensor 6, preparatory to delivery to external circuitry, not shown, byway of a cable or cord 7. Wireless sensor signal transmission is ofcourse possible by incorporating a power supply and transmitter with thecircuit board 6.

A conductor or conductors 8 are installed between pedestal 1 and cap 3for electrostatically shielding the pedestal cavity 14 and cap cavity31. Preferably, the conductors 8 may be made from resilient material inorder to add to resiliency between pedestal 1 and cap 3.

When a leg F of a bed or chair is placed on this bioinformation detectoras in FIG. 2, the sealing ring 2 will yield to the weight exertedthereon via the cap 3, thereby hermetically sealing the joint betweenpedestal 1 and cap 3 and hence the cap cavity 31 above the diaphragm 4.The physical vibration transmitted from the human or other biologicalentity on the bed or bed to the cap 3 will cause pressure variations inthe hermetically closed space. The strain sensor 5 will translate theresulting strain of the diaphragm 4 into a voltage signal. Received andamplified by the electronic circuit on the circuit board 6, the sensoroutput signal will be delivered over the cable 7 to the unshown externalmeans for measurement or observation.

The static air pressures in the pedestal cavity 14 and cap cavity 31 maybe independently adjusted and optimized as aforesaid by the pressureadjustment means 15 and 32. For instance, if the load weight from theleg F is found excessive, the adjustment means 32 on the cap 3 may beopened to permit air escape from the cap cavity 3 until the pressuredrops to a desired degree. The pressure in the pedestal chamber 14 maybe made equal to the atmospheric pressure by opening the pressureadjustment means 15 if the load weight is too light.

Notwithstanding the showing of FIG. 2, and as will have been understoodfrom the foregoing, the bioinformation detector according to theinvention need not necessarily be positioned in use with the cap 3directed upward. It will indeed function just as well if placed upsidedown, with the leg F loaded on the pedestal 1. Desired bioinformationwill be obtained equally well if the device is positioned either way.

Another preferred embodiment of the invention is shown in FIG. 3, inwhich parts corresponding to those in FIGS. 2 and 3 are identified bylike reference characters. This second embodiment includes the pedestal1 with a modified cavity 14 having a constriction 16 open to the capcavity 31. The other end, at the bottom of the pedestal 1, is open butis closed as the pedestal 1 is positioned on the floor 17.

The constriction 16 makes it unnecessary to close the open top of thepedestal cavity 14 with a diaphragm as in the previous embodiment;instead, the strain sensor 5 is mounted directly to the top of thepedestal 1 so as to close the constriction 16 of the pedestal cavity 14.

Thus the pressure variations caused in the cap cavity 31 will be applieddirectly to the strain sensor 6 via the constriction 16 therebystraining the strain sensor 6 and so causing the latter to develop aproportional voltage signal. The voltage signal will be amplified by theunshown amplifier on the circuit board 6, which is shown mounted to theoutside of the pedestal 1, preparatory to delivery to the externalequipment for measurement or observation. As in the previous embodiment,such signal delivery to the external equipment may be made without useof wires, by incorporating a battery and transmitter with the circuitboard 6. The pressure adjustment means 15 and 32 are of the sameconstruction and operation as their counterparts of the foregoingembodiment.

Two or more bioinformation detectors according to the invention, eachconstructed as in FIG. 2 or 3, may be put to combined use as in FIG. 4.Desired bioinformation will be obtained satisfactorily if only onedevice of the FIG. 2 or 3 construction is placed under one of the fourlegs of a bed or chair. Actually, however, such devices will have to beplaced under all the legs because the bed or chair would slant or becomerickety if only one is installed under one of its legs. It must also betaken into consideration that the weight of the object of measurementwill be distributed over large areas if it lies on something that has nolegs or like downward projections, such as a toilet seat, bathtub, orflooring. The embodiment of FIG. 4 is well adapted for suchapplications.

The part of the composite apparatus shown encircled in FIG. 4 is ofexactly the same construction as the bioinformation detector of FIG. 2except that the pressure adjustment means 15 and 32 are not shown forsimplicity. The caps of all the individual detector units of FIG. 4 areintegrally combined into what may be termed a platform 33. This platformis subject to change in both shape and size depending upon what is to beplaced thereon, for example, a bed, chair, toilet seat, and so forth.The subject of measurement may lie directly on the platform 33, eitherrecumbently or otherwise.

As has been mentioned in connection with FIG. 2, the individual detectorunits of FIG. 4 could be positioned upside down. In that case thepedestals 1, instead of the caps 3, of all the detector units might becombined into one platform.

INDUSTRIAL APPLICABILITY

The bioinformation detector according to the invention is applicable tomedical and healthcare fields, by being compactly attached to the legsof beds or chairs, toilet seats, or floorings for accurately capturinginformation from the biological objects resting thereon.

1. A bioinformation detector comprising: (a) a pedestal defining anopen-top pedestal cavity; (b) a diaphragm closing the open top of thepedestal cavity; (c) a cap mounted on the pedestal, the cap defining acap cavity open to the diaphragm; (d) resilient sealing means installedbetween the pedestal and the cap for hermetically sealing a jointtherebetween at least when the cap is loaded with an object ofbioinformation detection; and (e) a strain sensor attached to thediaphragm for sensing changes in air pressure in the hermetically sealedspace.
 2. A bioinformation detector comprising: (a) a pedestal defininga pedestal cavity having a constriction; (b) a cap mounted on thepedestal, the cap defining a cap cavity open to the constriction of thepedestal cavity; (c) resilient sealing means installed between thepedestal and the cap for hermetically sealing a joint therebetween atleast when the cap is loaded with an object of bioinformation detection;and (d) a strain sensor mounted to the pedestal so as to close theconstriction of the pedestal cavity for sensing changes in air pressurein the hermetically sealed space.
 3. A bioinformation detector as setforth in claim 1 or 2, further comprising pressure adjustment means foradjustably varying static air pressure in the pedestal cavity.
 4. Abioinformation detector as set forth in claim 1 or 2, further comprisingpressure adjustment means for adjustably varying static air pressure inthe cap cavity.
 5. A bioinformation detector as set forth in claim 1 or2, further comprising conductor means coupled between the pedestal andthe cap.
 6. A bioinformation detector as set forth in claim 1 or 2,further comprising conductor means of resilient material installedbetween the pedestal and the cap.
 7. A bioinformation detectorcomprising a plurality of bioinformation detector units each constructedas in claim 1 or 2, and a platform formed by integrally joining caps ofall the bioinformation detector units.